During the advancement of a catheter into the vasculature of a patient, there are several factors that must be taken into consideration. One of the more important considerations is the ability of the catheter to be accurately and properly guided through the vasculature into its intended location or position. An important adjunct of this is the ability of the catheter to be properly configured, if necessary, once it has been properly positioned. In some instances, such as when an over-the-wire catheter is being used, the guideability of the catheter is dependent on the proper pre-positioning of the guidewire in the vasculature. This is not so with other types of catheters. For instance, due to its unique functional refrigeration requirements, a cryocatheter must typically be positioned in the vasculature without the assistance of a guidewire. Furthermore, many catheters, such as cryocatheters, may need to be reconfigured once they have been positioned in the vasculature.
The need for being able to guide a catheter through the vasculature, without the assistance of a guidewire, has been recognized. Heretofore, however, systems for accomplishing this have relied on the catheter's ability to bend in a predetermined plane, and on its ability to be rotated so that the predetermined bending plane can be properly oriented. For example, U.S. Pat. No. 2,574,840 for an invention entitled “Flexible Medical Probe” which issued to Pieri et al., as well as U.S. Pat. No. 5,114,414 which issued to Buchbinder for an invention entitled “Low Profile Steerable Catheter,” both disclose systems for concertedly deflecting the tip, and rotating the body, of a catheter/probe to steer the catheter/probe through the vasculature of a patient.
It happens that, in addition to the ability to guide a catheter through the vasculature, more control over the catheter may be required. New procedures are now being perfected wherein it is necessary for the catheter to be reconfigured after it has been properly positioned in the vasculature. For example, in order to treat atrial fibrillation by cryoablating tissue, it is desirable to configure the tip of the catheter as a ring that can be placed in contact with tissue at an ostium where a pulmonary vein connects with the left atrium. Then, after the tissue around the ostium has been cryoablated, the catheter must again be reconfigured for withdrawal from the vasculature. In this procedure, as in others not mentioned here, there is a need for a catheter that has extensive flexibility for changing configurations.
In light of the above, it is an object of the present invention to provide an articulating segment for a catheter that allows the catheter to be selectively bent in any of several planes without rotating the catheter. Another object of the present invention is to provide an articulating segment for a catheter that allows the catheter to be simultaneously bent in different planes to effectively reconfigure the catheter, as desired. Still another object of the present invention is to provide an articulating segment for a catheter that can bend with a relatively small radius of curvature. Another object of the present invention is to provide an articulating segment for a catheter that can bend into a ring-shaped configuration. Yet another object of the present invention is to provide an articulating segment for a catheter, and a method for its manufacture, that is simple to implement, easy to use, and comparatively cost effective.